Gas fireplace installation manual call for 105c degree rating on all wiring in the unit. My feed to this fireplace will utilize 1/2 flex conduit. I have installed Southwire simpull wire which carries a thhn,mtw,awm designation. Installed in a dry location the awm is listed at 105c, ampacity of the fireplace is under 3 amps. the circuit picking up the fire place is a 20 amp general purpose circuit, simpull wires are a #12. Can I utilize the fact that its rated for 105c in a appliance wiring situation?
Dual Rating
- Thread starter eds
- Start date
- Status
Although I would be tempted to say "yes", the AWM conductor is not a NEC recognized conductor and is UR approved as a recognized component and not UL listed (or any other NRTL as far as I can see). If the wire came as part of the factory unit, no problem, but otherwise problematic IMHO.
kwired
Electron manager
- Location
- NE Nebraska
If you are hitting a designated supply box, which most these have, I don't believe it would typically require the high temp wire - that is probably what is required for any internal accessories you might connect.
Does it state anything about minimum temp rating for the supply conductors anywhere?
Does it state anything about minimum temp rating for the supply conductors anywhere?
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
But the OP said his conductor was both THHN rated and AWM 105C rated. So doesn't the THHN rating satisfy any NEC requirements?
Cheers, Wayne
kwired
Electron manager
- Location
- NE Nebraska
To NEC THHN is a 90C conductor and AWM is something not recognized by NEC so I think answer is no.The MTW rating maybe is, but I don't believe it is for premises wiring, so it would have to be something within the appliance.
Similar thing happens with THWN - good for 90C in dry locations but only good for 75C in wet locations. Then they come up with THWN-2 that is good for 90C in both.
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Sorry, maybe I wasn't clear. Here's my thinking:
The NEC requires the wiring to the unit to be a Chapter 3 method. THHN in 1/2" FMC is a valid Chapter 3 method. The NEC is satisfied.
The manufacturer's instruction call for the wiring to have a 105C rating. The wire is rated AWM 105C. The manufacturer's instructions are satisfied.
So where's the problem?
Cheers, Wayne
The NEC requires the wiring to the unit to be a Chapter 3 method. THHN in 1/2" FMC is a valid Chapter 3 method. The NEC is satisfied.
The manufacturer's instruction call for the wiring to have a 105C rating. The wire is rated AWM 105C. The manufacturer's instructions are satisfied.
So where's the problem?
Cheers, Wayne
No on the supply conductor rating, so to cover my bases i wanted to use a 105 degree rating
Make up box is 30'' or so inside the bottom of the fireplace
That was my logic also
kwired
Electron manager
- Location
- NE Nebraska
NEC doesn't recognize AWM period but does recognize THHN as being 90C conductor?
snippet of something I found on the topic "AWM is an acronym for Appliance Wiring Material. AWM conductors are UL recognized component wires evaluated for specific uses. Each style number has a specific use. ... Conductors identified as AWM may also be identified as a Listed building type conductor if evaluated for both sets of requirements and dually rated."
Seems to support what I was saying. If dual rated you can use this conductor as THHN for premises wiring but THHN is recognized as 90C. However in OP's case the portion that is within the appliance likely can use the AWM rating - so in his case it is probably fine.
Either way most fireplaces I have seen I doubt the main supply box ever gets hot enough that it should need a high temp rating, though conductors that leave this box and go to other parts of the appliance may need so beyond that point. It would be nicer if instructions clearly said a minimum supply conductor temp rating, what was mentioned seems to be talking more about what is needed inside appliance for optional accessories more so than what is needed for supply conductors.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Our church has several PAR-56 bulbs in metal enclosures on the ceiling. The wires from the lamp socket to the junction box are fiberglass insulated (would have been asbestos long ago), and the label on the junction box called for 105C supply wire, making dual rated wire necessary.
Sent from my XT1585 using Tapatalk
Sent from my XT1585 using Tapatalk
- Status